428 Transactions of the Society. 



Of these, the virga has a basal inflation in D. macrocephalus, 

 D. riggenbachi, D. raffrayi, D. gladiator, and D. lefroyi. 



As specific peculiarities, we note the strong denticulation of the 

 preputial sac in D. macrocephalus, its slight denticulation in 

 D. gladiator and D. liberatus. The plates show the specific 

 differences in the form of the metaparameres ; the presence of a 

 second smaller tooth should be noted in D. liberatus, and the form 

 of these parts in D. bormansi is quite characteristic. 



As to the genus Nannopygia Dohrn I feel sure that we are in 

 the presence of another of Verhoeff s mistakes, which has misled 

 Zacher. I am convinced as to the identity of my Cingalese speci- 

 mens with N. gerstseckeri of Dohrn, and my figure shows as quite 

 typical Diplatyne armature, whereas Zacher states that Verhoeff 's 

 specimen, with no indication of locality, has bifid metaparameres, 

 and places it with his N. picta from British East Africa. It is very 

 easy to make a mistake of identity in this group, and Verhoeff may 

 have had D. emesti Burr, or D. jacobsoni Burr, before him, in neither 

 of which are the genitalia yet known. Anyhow, the genitalia of 

 my D. gerstcvekeri are not, in my opinion, generically different from 

 those of the other species considered, and I maintain my long- 

 stated opinion, that Nannojiygia cannot be generically separated 

 from Diplatys. If it ever is, it will be upon the form of the 

 ninth sternite and forceps. 



Zacher's N. picta has a peculiar form of metaparamere which 

 would better justify a new genus than the virga, and approaches 

 the form seen in his figure of D. vosseleri Burr. In both the 

 metaparameres are broad and bifid, and on this I should be willing 

 to grant them generic rank ; in both there is a denticulate area in 

 the preputial sac. In D. vosseleri the virga is basally inflated, 

 and in D. picta it is decidedly longer. This is further evidence in 

 favour of my contention that the virga offers characters rather of 

 specific than of generic value. 



I should have felt inclined to give generic value to the form of 

 the forceps and last abdominal segment, but for the fact that 

 D. raffrayi differs in this respect from D. macrocephalus, yet agrees 

 with it in the form of the genitalia. 



But after all, a comparison of the figures shows that these 

 peculiar forms of metaparamere in D. vosseleri and D. picta are 



EXPLANATION OP PLATE VII. 



FIG. 



1. Cranopygia valida Dohrn. 



2. C. cumingi Dohrn. 



3. C. modesta Borm. 



4. C. sauteri Burr. 



5. Acrania eximia Dohrn. 



6. A. picta Guer. 



FIG. 



7. Acrania horsfieldi Kirby. 



8. Echinosoma occidentale Borm. 



(Entebbe.) 



9. Ditto, ditto. (Kamerun.) 



10. E. fuscum Borm. (Kuako.) 



11. Ditto, ditto. (Entebbe.) 



